Nondystrophic myotonias are muscle disorders caused by abnormal muscle cell membrane proteins that affect the control of muscle fiber contraction. These disorders are extremely rare, and little is known about how to best treat the various subtypes of NDM. The purpose of this study is to characterize the clinical features and symptoms of NDM as well as to pair this data with specific NDM subtypes. In turn, this may lead to the development of improved treatments. The study will also establish clinical endpoints for use in future studies.

This multi-center observational study will involve both a cross-sectional data analysis and a prospective longitudinal analysis. Participants will initially attend a one-day outpatient study visit. Various baseline measurements will be collected, including demographics, medical history, and quality of life measures. Blood samples will be taken to evaluate laboratory values and genetic factors. Participants will undergo manual muscle testing (MMT), clinical myotonia assessments, and functional movement assessments. Routine nerve conduction studies and electromyography (EMG) will also be performed in order to test for the presence of myotonia in specific muscles. Annual follow-up evaluations will occur 1 and 2 years following the first study visit.

Eligibility

Ages Eligible for Study:

6 Years and older

Genders Eligible for Study:

Both

Accepts Healthy Volunteers:

No

Sampling Method:

Non-Probability Sample

Study Population

Individuals with nondystrophic myotonia

Criteria

Inclusion Criteria:

Clinical symptoms or signs suggestive of myotonia

Presence of myotonic potentials on electromyography (EMG)

Persistence of symptoms and signs after discontinuation of medications that produce myotonia; such medications include fibric acid derivatives, hydroxymethylglutaryl CoA reductase inhibitors, chloroquine, and colchicine

Any other neurologic condition that might affect the assessment of the study measurements

Contacts and Locations

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study.
To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below.
For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT00244413

Locations

United States, Kansas

University of Kansas Medical Center, Department of Neurology

Kansas City, Kansas, United States, 66160

United States, Massachusetts

Brigham & Women's Hospital, Department of Neurology

Boston, Massachusetts, United States, 02115

United States, New York

University of Rochester School of Medicine and Dentistry, Department of Neurology

Rochester, New York, United States, 14642

United States, Texas

University of Texas Southwestern Medical Center

Dallas, Texas, United States, 75390-9036

Canada, Ontario

London Health Sciences Centre, University Hospital

London, Ontario, Canada

United Kingdom

Center for Neuromuscular Disease, Institute of Neurology and National Hospital for Neurology